This invention relates to endotracheal tubes, and, more particularly, to an endotracheal tube having a distal end which can be manipulated to facilitate intubation in the trachea of a patient.
Endotracheal tubes have been used for a number of decades to prevent upper airway obstruction or to facilitate artificial ventilation of unconscious or anesthetized patients. Standard endotracheal tubes comprise an elongated, flexible air tube which is curved or arcuate-shaped between its distal end and proximal end for insertion through the upper airway passages into the trachea. An inflatable bag-like structure or cuff is disposed about the exterior surface of the air tube at the distal end which is inflatable after the tube is in place to create an air-tight seal between the tube and tracheal wall. This prevents air being pumped by a respirator connected to the proximal end of the tube from escaping retrograde through the trachea and entering the oral and nasal passages.
The arcuate shape of prior art endotracheal tubes is intended to duplicate the path of the air one inhales so that when the distal end of the air tube is inserted through the oral or nasal passage it slides directly into the trachea instead of the esophagus. Conventional intubation techniques include inserting a laryngoscope into the mouth to anteriorly displace the tongue, lift the epiglottis and directly visualize the larnyx to intubate the trachea. Intubation of the trachea through the nasal air passages is more difficult because the pathway from the external nares into the trachea is circuitous and requires two bends of the endotracheal tube, virtually at right angles to one another. For some patients, intubation of the trachea either through the oral or nasal passages is routine.
In other patients, the intubation procedure can be difficult even for trained personnel. A difficult intubation may be anticipated in patients with short muscular necks, receeding jaws, large thick tongues, high arched palates, cervical spine or madibular immobility, hematoma, abcess or inflammation around the posterior pharynx or larynx, facial fractures or anatomical deviations from normal.
In order to perform the intubation procedure correctly, the distal end of the tube must be inserted within the trachea so that the lower cuff is positioned a few centimeters below the larynx to seal the trachea when inflated. Prior art endotracheal tubes are formed of a flexible plastic material to permit at least some deflection of the distal end of the tube during intubation by manipulating the remaining portion of the tube. However, once the distal end of the tube approaches the trachea and contacts the laryngeal region, it can become difficult to guide the distal end by manipulating the remaining portion of the tube. This is a particular problem for the conditions described above in which a difficult intubation can be anticipated. Because of the difficulty in controlling the movement of the distal end of prior art endotracheal tubes, intubation is often performed unsuccessfully either by failing to direct the tube a sufficient distance past the vocal chords or by moving the tube anteriorly into the esophagus.
The problems with the intubation procedure outlined above have been recognized in the prior art, and endotracheal tubes, catheters and stylets have been proposed which provide for controlled movement of the distal end during intubation. For example, U.S. Pat. Nos. 3,470,876; 3,605,725; and 2,498,692 all disclose catheters or tubes having an inner wall, an outer wall spaced from the inner wall and two or more spaced passageways formed between the inner and outer walls. Each of the passageways receives a line which is fixed at the distal end of the tube or catheter, and which is connected to a tensioning device mounted externally of the tube or catheter at its proximal end. Movement of the distal end of the tubes during intubation is achieved by selectively pulling or tensioning the lines with the tensioning devices, which, in turn, causes a deflection of the distal end fixedly connected to the lines.
The problems with the designs disclosed in the prior patents mentioned above are many. The tensioning devices for the lines, which are mounted exteriorly of the tubes in the patents mentioned above, are cumbersome, complicated and add substantially to the cost of the tubes, catheters or stylets which are disposable and not intended for reuse. In addition, at least a portion of each line at the proximal end of the tubes is exposed and could be broken or otherwise damaged prior to or during an intubation procedure. The endotracheal tubes and catheters in the prior art often require both hands to intubate the trachea which increases the difficulty of the procedure, particularly in certain patients as discussed above.